I had the issue with the launcher and config all working fine but when I started the game itself, it'd seem to start fine but not show on the screen. This is with 'Ubuntu Gnome' and the default Gnome desktop. Turns out the launcher was keeping the focus and the game was being stared hidden. I could alt-switch to it.
Disabling "Allow the window manager to control the windows" fixed this. Took a bit to figure out and thought I'd share to try to shortcut someone else's fiddle time.